Dietary fiber is a term for a variety of plant substances that are resistant to digestion by human gastrointestinal enzymes. Dietary fiber supplements contain naturally occurring plant fiber such as psyllium, semisynthetic fiber such as methylcellulose or synthetic fiber such as calcium polycarbophil.
Dietary fibers can be divided into two groups, based on their water solubility. The structural or matrix fibers, cellulose for example, are insoluble. The natural fibers, pectins for example, are soluble.
The addition of fiber to the human diet has attracted increasing interest in recent years as the shortcomings of the diets of western countries have become known. The current prevalence of diseases including diabetes, coronary heart disease, colorectal cancer and gastrointestinal disorders such as constipation, hemorrhoids and diverticular disease, are associated with, among other things, diets containing more fat and less fiber.
It has been suggested that increasing dietary fiber intake may help prevent many diet-related disorders and/or mitigate their course. The American Diabetes Association and National Cancer Institute recommend diets high in fiber and complex carbohydrates and low in fat. Physicians and pharmaceutical companies have attempted to correct the deficiency of dietary fiber with products that struggle to achieve this purpose.
Because Westernized diets are made up of so many highly processed, low-fiber foods, it takes a concerted effort to begin a high-fiber dietary habit. However, it must be remembered that it is extremely difficult for most people to make major changes in eating habits. Therefore, the use of dietary fiber supplements is becoming more widespread.
Currently available fiber supplements include Metamucil.RTM., which contains psyllium as the active ingredient; Citrucel.RTM.--a methylcellulose composition supplied in powder form; Fibercon.RTM., which contains calcium polycarbophil as the fiber source.
U.S. Pat. No. 4,988,530--Hoersten et al.--is drawn to a beverage containing pectin having a degree of esterification of at least 50%. Hoersten et al. discloses the two groups of dietary fiber, insoluble fiber and soluble fiber, and identifies the problems associated with using each group as a fiber source in food products. When incorporated into liquid food formulations, the insoluble dietary fibers are difficult to maintain in proper suspension or dispersion and tend to settle to the bottom of drinks and beverages. Additionally, the insoluble dietary fibers provide the liquid foodstuffs with a gritty texture and are not particularly pleasant tasting.
Because of their solubility, the soluble dietary fibers do not have a gritty texture associated with their use. The soluble fibers, however, tend to thicken liquid products and can affect the original sensory mouthfeel of the unmodified liquid. The Hoersten et al. patent also recognizes the obstacles in the use of carboxymethylcellulose as a liquid dietary supplement. The addition of carboxymethylcellulose to water or juice was thought to require prompt consumption or the solution would result in thickening to the consistency of partially set gelatin or wallpaper paste.
Additional related art includes U.S. Pat. No. 3,455,714 which discloses cellulose derivatives with a water soluble cellulose ether coating to improve the dissolution of insoluble cellulose fibers in water, however, a beverage or liquid form of the water-soluble composition is not disclosed; and
U.S. Pat. No. 4,321,263 discloses coating psyllium with a polyethylene glycol-polyvinyl pyrrolidone composition also to improve dispersability of psyllium in water.
Accordingly, there exists a need for a dietary fiber supplement available in a liquid dosage form, containing methylcellulose, thus making the addition of fiber to one's diet pleasant tasting and effective.